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November 4, 2008 A Penton Media Publication Vol. IV No. 21


CONTENTS
Fire Pump OCPDs

Maintaining for Energy Savings, Part 1

Electrical Troubleshooting Quiz

Motor Windings Speak From the Grave

NEC in the Facility

Safety

Answer to Electrical Troubleshooting Quiz


About This Newsletter
This twice-a-month
e-newsletter is brought to you from the publisher of EC&M magazine.

MRO Insider addresses topics such as:

  • Working with management and supervision
  • National Electrical Code® on the production floor
  • Safety procedures and programs
  • Troubleshooting techniques
  • Equipment maintenance and testing tips
  • Managing motors and generators
  • Trends in training and education
  • Managing energy use


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    Maintenance
    Fire Pump OCPDs
    Overcurrent protection devices (OCPDs) normally protect equipment and conductors from overload. With fire pumps, this isn’t true. Fire pumps must run no matter what (almost).

    To prevent saving the pump from overload while the building burns down, Art. 695 requires the OCPDs to be capable of carrying the fire pump motor load indefinitely.

    Fire pump OCPDs provide short-circuit protection only. The pump can’t run with a short anyway, so you aren’t losing pump function due to the OCPDs. You may even have a chance to restore operation.

    You can’t protect fire pump conductors from overload with OCPDs, so prevent overloads from occurring in the first place. To do so, maintain the system per NFPA 25 and ensure it conforms to NFPA 20.

    If you think the OCPDs might be oversized, review OCPD sizing per Art. 695. Obtain approval for resizing from the Fire Marshall (and other applicable AHJs), to protect your insurance coverage and your facility.


    Maintaining for Energy Savings, Part 1
    The focus on energy savings seems to be on lighting, with little said about maintenance. This leaves money on the table. In future issues of this newsletter, we’ll examine how to tap that particular piggybank.

    However, before we do, let’s address a common misperception in the lighting recommendations and coming regulations.

    It’s true that replacing old fluorescent ballasts and lamps with more energy-efficient ones reduces energy waste without requiring a lighting redesign. But not all lamp replacements produce such positive results.

    Whether you save energy by replacing incandescent lamps with CFLs depends on the application. It takes energy to make gas fluoresce. Once it’s glowing, it uses much less energy to stay glowing. An incandescent lamp requires more energy to run, but much less to start than a CFL. Therefore, a CFL has to run for some time to “catch up” with the incandescent in terms of total energy savings.

    For momentary lighting, such as in a closet, incandescent lamps are more energy-efficient than CFLs. Just slapping in CFLs won’t necessarily reduce energy waste. When relamping, consider usage and technology.


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    Repair
    Electrical Troubleshooting Quiz
    Your fire pump runs for no apparent reason almost daily. Unfortunately, that across-the-line start throws all kinds of power anomalies into your system. Your power monitor shows additional power anomalies when the pump shuts off. The toll on electronics is getting management’s attention. What should you do?

    The motor shop informs you the bearings are severely pitted. What problem is this an indication of, and what condition is most likely causing it?

    The answer to this question appears at the end of this newsletter.


    Motor Windings Speak From the Grave
    A repair is complete only when the failure cause is identified and corrected. Motor windings can tell you what the failure cause is, if you understand the language they speak. Their vocabulary consists of burn marks, broken windings, and debris in the windings.

    • Burn marks. These indicate a power distribution problem that’s degrading your winding insulation.
    • Broken windings. The usual cause is excessive thermal stress.
    • Debris. Debris in the windings typically means you need better housekeeping around the motor. Examine the debris closely to determine its source.
    What about “cooked” windings? If all of the stator windings look “aged” or “baked” from excess heat, then you have voltage imbalance. If only two-thirds of the windings have this look, you have single-phasing.



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    Operation
    NEC in the Facility
    If your site has hazardous locations, have you reviewed them lately? With changes in configuration, materials, processes, and equipment, area classifications might also need to be changed to avoid:
    • Incidents. If existing procedures are insufficient due to underclassification, then your company carries undue risk of an incident.
    • Underinsurance. Your company may lower its financial risk by upping coverage so it’s adequate for present conditions.
    • Overinsurance. Your company may be able to lower its insurance costs based on reclassification of one or more areas on site.
    Article 500 provides the foundation for understanding the hazardous location requirements in Articles 501–506. Take time to learn it.


    Safety
    In its early days, infrared thermography cost far more than it does today. Even then, the benefits easily justified the cost. One of those benefits was improved safety, mostly due to not having to manually connect test leads.

    It’s important to understand that thermography, like any other electrical work, is not inherently safe. To conduct thermography, you must open enclosures and be exposed to various dangers, such arc blast from equipment on which you’re not even working. Today’s thermographic cameras have many useful features, but arc blast protection isn’t one of them.

    NFPA 70E tables are based on the energy levels present in the equipment being worked on. Nowhere does NFPA 70E say those tables apply, “…only if you’re holding test leads.”

    NFPA 70E tables also apply to plant managers and corporate execs who are tapping away on their Blackberries while “observing” the ongoing work. Arc blasts don’t care what your title is.

    It’s best that nonessential personnel leave the test scene — period. Internationally recognized safety expert Paul Hartman, currently with Power Testing and Energization (an electrical testing firm), advises nonessential personnel to follow this simple safety practice: “Don’t be there.”


    Quiz Answer
    Answer to Electrical Troubleshooting Quiz
    This problem has a 3-step solution.

    The first step is to determine why the pump is operating at all. If there’s a leak in the piping, it’s better to discover it now than to have a pipe fail during a fire. Contact a qualified firm to test your fire protection pipe integrity. In an actual case of this problem, the operators were using the fire pump system as a source of washdown water. Don’t permit such use. Testing or flushing the system is one thing; using it regularly for non-protection purposes is another.

    The next step is to determine why the jockey pump isn’t making up pressure. Check the controls for that pump as well as for the main fire pump.

    Your final step is to reduce the severity of the power anomalies. Check with your local AHJ and your insurance company about the requirements for installing a softstart on that fire pump (for example, it will need a manual bypass). You will need an engineered solution, so be prepared to spend time and money to get it right.


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